Electrical apparatus



June 8, 1943. w. A. ToLsoN 2,321,335 4f fv l ELECTRICAL APPARATUS 4 JSJC? f F11 ed sept. 30, 1940 i 2 Sheets-sheet 1 f/3'W- A @l T fr TT -lllllmuentor IMM ` ftorneg June 8 1943 w. A. 'roLsoN 2,321,335 f ELECTRICAL APPARATUS l Filed sept. zo, m40- 2 sheets-sheet' 2 I i F14? 05%' Slwcntor blfa a -frequency.

Patented 'June 8, 1943 UNITED STATES lIPA'IEN'F -oFFlcsl Radio Corporatio'nof America, a-corporation of I Application September' 50,1940, S.eral-No`.'359,1'70

2; Claims. (01; ,-l'zgsQj-vsf This invention relates to delay circuits,v and,

Inoref'particularly to 'anel'ectronic time delay device. In the transmission of j serious loss in picture trans'znlssion time is occasioned by the loss in time required forv the syn-' .chronizing signal/to actuatethe deflectin'g oscillator and for the transmission of the saw-tooth deflecting signal to the picture tube. It has been estimated that the total time lost in the vhorizontal scanning circuit' represents about 5 per-x cent of the total picture time exclusive of the vtime lost due to the return line time.

It has been proposed that a time delay network be included in the video amplifier circuit of the television receivers to delay the video signals ony the control electrode of the picture tube by a time equivalent to the time lost in the synchronizing and deflecting circuits. In this manner, approximately 5 percent of the total picture transmission ltime would be saved.` In practice, however, a

vtime delay network comprising inductanceand capacity would be' extremely elaborate and very critical of adjustment if the attenuation and phase-delay characteristics were to be maintained constant over the wide frequency band:

required for the production of a high definition television picture.

It has been found that a -ffeifrweayeiectron beam can be produced by using anelectron discharge device having a cathode adapted to emit' electrons and an anode adjacent the cathode and subjected to a relatively low `positive potential withl respect to the cathode. In such a device the transit time of the'electrons may be increased: by employing known types of electron guns andv y projecting the stream of electrons upon an element located at a relatively large distance from the cathode.

According to this invention, a transmission time delay is secured through the use of such a flow velocity ,electron beam. An electronic delay device has the advantage over a filter network in that the delay .characteristic would be completely independent of frequency and the amount of delay may be very conveniently adjusted.

The primary object of the present invention is to provide anelectronic transmission-time delay device.

Another object of this invention is to provide a transmission-time delay device whose delay characteristic is completely independent of Still another object of this invention is to provide a transmission-time delay device whose'A delay characteristic may be easily adjusted.

'I @ther and incidentalobjects of the invention will be apparent to those skilled in the art from a reading of the following speci'cation and an vin. spect-ionof the accompanying drawings in transmission-time delay network,

Figure 3--is5 a circuit diagram showing one embodiment of this invention,

-Figure- {lisa cross-sectional view of another form" of electronic transmission-time delay clevice,v and 4 Figure5 is a sectional view of Figure 4.

Referring-now -in more detail -to Fig. 1, an elongated envelope -I contains a heater element 3 and acathode 5, a control electrode 'Lan anode 9 and an auxiliary electrode II.

The cathode 5 is widelyseparatedfrom the anode 9, and', by using an extremely low anode potential, an extremely llow velocity beam of electrons is caused -to pass from the cathode 5 to the anode i9. -The control electrode 'I is used to modulate the intensity vof the electron beam flowing from the cathode 5 to the anode 9.

' Since'4 a load would normally be included in the anode circuit, the `anode voltage would vary in accordance, with the signals impressed upon the control electrode -'I. For thisreason, a screen electrode or acceleratingelectrode- I I is positioned adjacent the `anode 9 to prevent Imodulation of theV electron-velocity due to the resulting signal voltages on lthel anode.

Fig.'2 showsa circuit comprising a plurality of inductances L and capacitors C whose electrical characteristics are equivalent to the electron discharge device-'shown-and described under Fig. 1.

Fig. 3 shows the use of an electron time delay device in a television image reproducer wherein the signal from the radio frequency and intermediate frequency'amplier I3 is fed to a second detector I5. Signal from the second detector I5 is fed through the synchronizing signal separator and amplifier shown as block Il. The vertical pulses are fed through the vertical deflection pulse generator I9 to the vertical deiflecting coils -2I of the picture tube 23. The horizontal pulses from the synchronizing signal and separator I'I are fed through the horizontal defiecting pulse generator 25 tothe horizontal delecting coils 21 of the picture tube `23.

A portion of the signal from the second detector I5 is impressed upon the control electrode 'I of the electronic ltime delay device 29. An auxiliary electrode II is supplied with a small positive potential by voltage source SI and the anode 9 is supplied with a'small positive potential through voltage source 33 and coupling resistor 35. The delayed signal from the electronic time delay device 29 is -fed to the video amplier 31 from the anode 9 and through the coupling condenser 39. The delayed video signal is then ltrede y5.9, and a firstV anode cathode 55 such that the transmission .of the synchronizing pulses through the synchronizing' signal separatorand amplifier circuit I1, andthedeectionpulsegen'lator cir-' of the total picture transmission time "willfbe saved by eliminating the out the picture signal during the additional time required for-:the Vtransmission of the synchronizing v pulses through their associated circuits.'

, 'Ihe transit time of the-electrons may be -still further increased by so arranging' the elements andcircuit constants that. the electron stream doesnot actually reach the,` target elementibut is fcaused to .-returnto `a, second target element adjacent to .-the cathode. This'eiect is produced A Iams No. 2,213,177, `issued,August. 27,y 19,40.-

Figure 4 shows an electronic transmission-time delay device having an envelope 5|v containing an electron gun having a heater element 53, aVv cathode 55, a control electrode 51, an auxiliary elec- 6| ,which generates The magnetic effect of thezvdellectir 1.g

directs the electron beam 69 towardan auxiliary anode 1| positioned at anopposite end of,tube

The electrons of beam 69 are thendrcctedto- Ward another auxiliary anode-13 :at the same end of the tube as thecathode sabut dismaetherefrom by a distance equal to the lateral distance other auxiliary anode15, a slightly positive potential with. electrons eam 69 are allowedtostrike the respect to the condenser 8|. The resistor 8,3 is connected to the ltime lost in the necessity for b lanking of. the electron auxiliary anode control electrode 51 to allow accumulated electrons to leak off to ground.

Figure 5l Vis a, sectional 'view ot Fig. 4 showing more clearly the deflection coils 61 which take the form of rectangular coils bent over the envelope 5|. 'Ihe directing coil 65 is in the form of a circular coil surrounding the envelope 5|. The anode 63, as previously described, takes the shape of a cylinder whose ends are closed with the exception of -small openings 85 and 81 which are positioned inffrontl of the electron gun and the auxiliary =.anode 13, respectively. Similar opencuits I9 and 25, so that "app'ITOXiInatelys .percent izo ingsarey positioned in front of the auxiliary annees V-11 .and 15.

,by-"employing ffreection of the electron beam, the transit time of 'the lelectrons may be made verylorig.v I 1.

f Other applications f such-a device immediately suggestjthemselves-. 'For example, in synchronizing signal generators for use in the transmission ofV television signals, the'delay device would provide, .for easy and ment' of time delay betweenthe verti zontal'synchronizingimpulses t' `In'.`sing-le frequency duplex telephony, such a ,de'vicewould provide for the necessary delay in the speech inputcircuits to allow the transmission-actuating circuits'to function,

Whilefseveral systems for carrying this inventicular organisations show n and described', but

that many modifications 'maybe made without departing,from"the scope of this invention asisjet Vfortlrin'nl the appended claims.

I claimfasV invention; l'1' I n ja picture 'reproduc ignal channel v and said beam deis delayed'more than' the signal passing through saidsign'al amplifier, the com signal'fchannel of an electronic WILLIAM A. ToL'soN. 

